A variety of measurement and control systems make use of multi-range measurement apparatus (i.e., apparatus that is capable of measuring a signal via one or more of a plurality of selectable gain stages).
Before its initial use, a multi-range measurement apparatus is typically calibrated. Calibration involves measuring a characteristic of the measurement apparatus itself, and then using the measured characteristic to adjust measurements made in the normal course of using the measurement apparatus. One common form of calibration involves “zeroing” the measurement apparatus (i.e., measuring an offset voltage or other characteristic of the measurement apparatus, so that the offset voltage or other characteristic can be used to adjust measurements made in the normal course of using the measurement apparatus).
Calibration may be repeated on a periodic or non-periodic basis (e.g., after use for a particular number of hours, after deployment in a new measurement setup, after an environmental change, or after certain changes in the signal being measured). Typically, each range of a multi-range measurement apparatus is calibrated (or “zeroed”) independently and serially. That is, a first range of the measurement apparatus is selected and calibrated; then, a second range is selected and calibrated; and so on, for each range of the measurement apparatus.